Is there a generic way to lookup what a hotkey/shortcut does under current user prefs?
Yes, there is.

You can go to Setting &gt; Keymap, here is all the input event user does.

And up there is a search bar. With Key-Binding search method selected, you can search your short cut by key.



If you are using 2.79b for an old favor. The same panel is in user preference &gt; Input.

And the sequence of what you tap when operator is running (the second R) is inside the modal group keymap, you need to expand the action group to see it.